Down-Regulated Expression of RACK1 Gene by RNA Interference Enhances Drought Tolerance in Rice

The receptor for activated C-kinase 1 (RACK1) is a highly conserved scaffold protein with versatile functions, and plays important roles in the regulation of plant growth and development. Transgenic rice plants, in which the expression of RACK1 gene was inhibited by RNA interference (RNAi), were studied to elucidate the possible functions of RACK1 in responses to drought stress in rice. Real-time PCR analysis showed that the expression of RACK1 in transgenic rice plants was inhibited by more than 50%. The tolerance to drought stress of the transgenic rice plants was higher as compared with the non-transgenic rice plants. The peroxidation of membrane and the production of malondialdehyde were significantly lower, and the superoxide dismutase activity in transgenic rice plants was significantly higher than those in non-trangenic rice plants. It is suggested that RACK1 negatively regulated the redox system-related tolerance to drought stress of rice plants.